LTE reception boosted by MEMS device

SANTA CRUZ, Calif.—Dutch MEMS maker Cavendish Kinetics B.V. said Monday (April 15) that its long-awaited NanoMech radio frequency (RF) MEMS chip will be shipping inside mobile phones by this holiday season. The device aims to boost the quality of mobile reception using an array of capacitors on a CMOS chip and MEMS switches to perform adaptive antenna impedance matching as well as frequency-tuning, filter-tuning and power-amp-load tuning.

According to Dennis Yost, Cavendish president and CEO, the quality of mobile reception is getting worse because mobile devices are degrading RF signals because of more interference from touch-screens and people's hands which are constantly changing the parameters for good reception. At risk today is wide adoption of LTE mobile devices, which make the highest demands on the electronics receiving these wireless broadband signals.

"What LTE devices need is adaptive frequency tuning and impedance matching for their antennas, along with tunable power amp loading and eventually tunable filters and duplexers," said Yost.

Cavendish Kinetics can make the entire radio frequency (RF) front-end module (FEM) tunable, with customers tackling antenna tuning and impedance matching in 2013, with tunable power-am loading to appear in 2014 and tunable filters and duplexers due out in 2015-16.

Cavendish's combo switch and capacitor array is fabricated with standard CMOS processing steps, but uses a proprietary technique that encapsulates the MEMS elements inside chip micro-cavities that isolate the moving parts from contaminants without the extra step required by other MEMS switched capacitor arrays.

The first device provides 32 switched capacitor values in a chip-scale package not much larger than a conventional single value capacitor. Inside the chip there are actually hundreds of capacitors, but the MEMS switches configure them into 32 distinct values. The first mobile phone using its switched capacitors arrays for antenna-impedance matching will appear before the end of 2013.Related stories:

So this technology uses MEMS to fabricate ultra-tiny replacements for electromechanical relays? Does this mean that other proven technologies such as PIN diodes are not feasible at these frequencies and/or power levels, perhaps due to a high level of "stray" capacitance? Why not "tune" the circuits using varactor diodes to vary capacitance, is it technology or just an IP licensing issue? The context fails to clarify the matter.